Drill bit



Nov. 10, 1936. F. A. THAHELD 2,060,354

DRILL BIT Filed Aug 1, 1935 2 Sheets-Sheet 1 /s 2 1m /&

Fem A. 7A 5/1 9/0 Patented Nov. 10, 1936 DRILL BIT Feri A. Thaheld, Dallas, Tex., assignor to The Guiberson Corporation, Dallas, Ten, a cog-poration of Delaware Application August 1, 1935, Serial No. 34,180

9 Claims.

This invention relates to new and useful immovements in drill .bits.

V One object of the invention is to provide a drill bit having improved means for rotatably securing the usual cutters thereon.

An' important object of the invention is to provide a drill bit having cutter axles for receiving conical cutters, together with rollers for rotatably fastening the cutters on said shafts, each roller having an undulating or corrugated surface, whereby said corrugations not only serve to hold the cutters in place but also provide an increased surface for bearing the thrust during the cutting operation.

Another object of the invention is to provide an improved drill bit having inclined axles for carrying the cutters, each axle and the bore of its cutter being formed with annular corrugations, whereby rollers having complementary corrugations may be inserted between the axle and cutter to rotatably confine said cutter on the axle, the rollers being readily removable which makes for .easy and quick assembling and dismantling of the drill bit.

A still further object of the invention is to provide an improved drill bit structure wherein the axles on which the cutters are mounted, are made separate from the bit body and may be readily welded, or otherwise fastened thereto, which permits the cutters to be mounted on their axles prior to the securing of the axles to the bit, whereby the mounting of the cutters may be more readily accomplished and the entire assembling simplified.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and 40 by reference Eto the accompanying drawings, in

which an example of the invention is shown, and

wherein:

' Figure l is a view partly in elevation, and partly in section of a drill bit, constructed in' accordance with the invention,

Figure 2 is an enlarged cross-sectional view, taken on the line 2-2 of Figure 1,

Figure Sfs a view, partly in elevation and partly in section of another form of the invention,

Figure 4'is an elevation taken at right angles to Figure 3, I

Figure 5 is an isometric view of the bit body and one of the axles, and

Figure 6 is a vertical, sectional-view of one of the cutters showing the direction of thrust thereon.

In the drawings, the numeral Ill designates a bit body or head having a reduced, tapered pin I l, or other drill stem connection at its upper end. 5 The lower end of the pin is surrounded by an outwardly directed shoulder l2. The body is provided with depending legs, or hangers l3 which have their inner sides I3 inclining inwardly and upwardly toward the center of the body (Figure 10 1). Each hanger is provided with an inwardly extending inclined cutter axle or shaft. M, the axles being disposed-at substantially a right angle to the inner surface I3 of the hanger. It is noted that the axles are in the same horizontal plane 15 and are diametrically opposite each other.

The outer surface of each axle is formed with annular ridges or corrugations l5 which are spaced apart'and cover substantially the entire length of said axle. The lower, outer edge of each axle is beveled at I6 and this bevel is provided with an annular recess or groove l6',-whichis semicircular in cross-section. A conical cutter H is mounted on each axle and each cutter is provided with suitable cutting teeth IS on its exterior surface. The teeth are shown extending longitudinally of the cutter, but it is pointed out they may be of any desired construction. Since the'mounting of the cutters is exactly the same, it is believed a description'of one will sufllce.

Each cutter is provided with an enlarged cylindrical axial bore l9 which is arranged to fit over the axle shaft. The bore has a diameter greater than the diameter of the axle whereby when the axle is inserted in the bore, an annular space 20 is provided between the outer surface of said axle and the inner surface of the bore. The depth of the time is substantially equal to the length of the axle and the bottom of the bore is provided with an annular groove 2 I, semi-circular in crosssection and complementary to the annular groove IS in the axle. Thus, when the axle is inserted in the bore, the grooves register, whereby a raceway is formed to receive ball bearings 22. These -balls beingat the bottom of the axle absorb the longitudinal'thrust upon the cutter.

For rotatably securing each cutter to its axle, the inner wall of the 'bore of each cutter, is formed with annular ridges or corrugations 24- which are complementary-to the corrugations I5 of the axle, whereby corrugatedrollers 25 may be inserted in the annular space 20 around the axle.-

The'roller's are entered into the space 20 through an inclined cylindrical opening 26 in the hanger or leg of the bit. A portion of the corrugations l6 and 24 arecut away at 21 (Figure 2) to permit insertion of the rollers, and thus, it will be seen that suillcient rollers may be entered to com pletely fill the space 20. After the rollers are in place, an elongated pin 28 is placed in the opening 28 and is of sufllcient length so that its lower end terminates in alinement with the inner inclined side I8 of the hanger member IS. The pin is welded, or otherwise secured, in said opening and serves to prevent the roller in the cutout portion 21 from being displaced upwardly. It is obvious that the engagement of the corrugations of the roller with the corrugations'of the bore and axle rotatably hold each cutter on its axle.

In this type of drill bit, the conical cutters l7 rotate to perform the cutting operation upon the slippery bottom of the well'hole only by the traction of their teeth and therefore, it is essential that bearing friction be reduced to a minimum. It is obvious that with the elongated corrugated rollers and the ball bearings, bearing friction is greatly reduced and also due to the length of the rollers, the bearing area is greatly increased because rollers will outwear ball bearings which are usually employed'in the ordinary cone cutter drill.

Since the bottom of the cone performs the cutting operation, there occurs an increased upward thrust against the rollers 25. The corrugations are so formed that one of thesurfaces 25' of each corrugation is substantially at a right angle to the direction of this thrust, as shown by arrows in Figure 6. There, these surfaces 25, co-acting with the registering corrugations of the rollers and shaft, take the thrust and since a plurality of corrugations are providedan increased thrust area, throughout the length of the bore is provided. Further, the corrugations provide an increased bearing area which increases the life of the bit. From the above, it will be seen that the ball bearings take any longitudinal thrust and also make for easier rotation of'the cutters, while the elongated rollers absorb the transverse thrust and provide increased bearing surface, The entire bit maybe readily dismantled by merely removing the pin 28 and then removing the rollers. Assembling is Just as quick and simple.

In Figures 3 to 6, I have shown another form of the invention. In this form the axles are made separate from the body which is formed with circular hanger members 30 having inclined inner surfaces 30.. The hanger members are preferably integral with the bit body and are reinforced by webs ll. The lower end of each web and the hanger is formed with a rectangular slot 32 which is arranged to receive a central triangular shaped rib 33 formed on theouter side of a circular plate 34. When the rib is inserted in the slot, the plate lies contiguous to the inner face 30 of the hanger, as clearly shown in Figure 3. Depending in this latter form the cutters may be mounted on the axles before said axles are fastened to the bit body. This feature makes for more convenient assembling and dismantling of the entire bit. It is pointed out that no claim is made in thi application to. the particular actuation of the cone, as said cone may have any actuation, either as shown herein or as set forth in my Letters Patent No. 2,020,625, issued November 12, 1935,

in which the invention herein is employed as a mounting.

What I claim and desire to secure by Letters Patent is:

1. A drill bit including, a body, axles carried by the -body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, and roundingly corrugated rollers located in the bore of each cutter and surrounding each axle for rotatably mounting each cutterand retaining it withthrust resistance on its axle.

2. A drill bit including, a body, axles carried by the body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, roundingly corrugated rollers located in the bore of each cutter and surrounding each axle for rotatably mounting each cutter on its axle, the wall of .said bore being correspondingly annularly grooved to receive said rollers. and means in the body for introducing said rollers one at a time into the bore of each ouster after said cutter has been placed on its a e.

3. A drill bit including, a body, axles carried by the body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, and roundingly corrugated rollers located in the bore of each cutter and surrounding each axle for rotatably mounting each cutter on its axle, the wall of said bore be-- ing correspondingly annularly grooved to receive said rollers, said body having an opening adjacent each body axle and cutter bore whereby the rollers may be introduced one at a time into the bore of each cutter after said cutter-has been placed on its axle.

4. A drill bit including, a body, axles carried by the body, a conical cutterarranged to be mounted on each axleand having a bore for receiving the axle, roundingly corrugated rollers located in the bore of each cutter and surrounding eachaxle for rotatably mounting each cutter on its axle, the wall of said bore being correspondingly annularly grooved to receive said rollers, said body having an opening 'adjacent each body axle and cutter bore whereby the rollers may be introduced one at a time into the bore of each cutter after said cutter has been placed on its axle, and a closure plug insertable in the openings for preventing outward displacement of the rollers."

5. Adrill bit including, a 'booy, diametrically opposite hangers at the lower end of the body, an inclined axle carried by each hanger,'a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, and

roundingly corrugated rollers located in the bore of each cutter and surrounding each axle for rotatably mountingeach cutter on its axle and the body axle and cutter bore being correspondreceiving the axle, each axle and bore having.

complementary rounded corrugations, and elon- 7 '1. A drill bit including, a body. axles carried by the body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, roundingly corrugated rollers located in the bore oi. each cutter and surroundv ing each axle for rotatably mounting each cutter on its axle, the body axle and cutter bore beinglcorrespondingly corrugated to receive said roundingly corrugated rollers, and ball bearings disposed in the bottom of the bore or each cutter and. engaging the lower end oi! the axle for resisting end thrust and reducing the friction duringrotation of the cutter.

8. A drill bit eluding, a body, removable axles carried by the body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle, and corrugated rollers 10-, cated in the bore of each cutter and surrounding each axle tor rotatably mounting each cutter on its axle.

9. A drill bit including, a body, axles removably attached to the lower end of the body, a conical cutter arranged to be mounted on each axle and having a bore for receiving the axle,

- said bore having a diameter greater than the axle whereby an annular space is formed around the axle, the axle and bore having complementary annular corrugations, and corrugated rollers inserted in said annular space, the corrugations o! the rollers serving to hold the cutters on the axles.

FER! A. THAHELD. 

